DESCRIPTION (adapted from application's abstract): The NJCRI has been a unit of the Terry Beirn CPCRA since its inception in 1989. The NJCRI's long-term objective has been a commitment to the CPCRA scientific agenda. This agenda includes examining effectiveness of antiretroviral treatment strategies, beginning with first-line therapy through salvage therapies and addressing clinical management questions including the optimal time to initiate antiretroviral therapy, the markers that should trigger a change in therapy, and the use of resistance testing for making therapeutic decisions. The NJCRI's specific aims are to continue to recruit a substantial number of subjects to CPCRA protocols and to follow protocol guidelines for patient management and data collection in a meticulous manner. Other aims include extensive collaboration with other units in developing and implementing CPCRA objectives and recruitment of HIV-infected populations frequently under- represented in clinical trials. The NJCRI currently has 266 patients enrolled in CPCRA studies. The applicants anticipate enrolling and following at least 300 patients per year in each of the five years of the grant period. In addition to patients being followed in the Nelfinavir vs. Ritonavir (NvR) study, they will enroll 50 patients in Mycobacterium avium complex (CR-MAC) and 50 in Pneumococcal Resistance. In regard to the newer studies, the investigators plan to enroll 50 patients in CPCRA (FIRST), 30 in the interleukin 2 (IL-2) study, and 50 in Protease Inhibitor Progression (PIP). They will also have capacity to enroll additional subjects in forthcoming trials.